Rotary disc cutting device

ABSTRACT

Rotary disc devices are disclosed for use in removing paint or other surface layers from or otherwise treating the surfaces of wood, metal, and brick. Each device consists of a disc having a coiled blade length of the band saw type embedded therein with its teeth exposed.

[451 Aug. 28, 1973 United States Patent [191 Metz 2,718,654 9/1955 Draughn 15/236 R ROTARY DISC CUTTING DEVICE FOREIGN PATENTS OR APPLICATIONS 11/1951 15/93 R 12/1958 France 15/93 R 21 Appl. No.: 234,248

Related Application Data Primary Examiner-Leon G. Machlin [63] Continuation-impart of Ser. No. 107,328, Jan. 18, Attorney-Abbott Spear 1971, abandoned.

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UNITED STATES PATENTS 3,216,041 Walters 15/236 R 12 Claims, 10 Drawing Figures Patented Aug. 28, 1973 3 Sheets-Sheet l Patented Aug. 28, 1973 3 Sheets-Sheet Patented Aug. 28, 1973 3 Sheets-5hect 3 ROTARY DISC CUTTING DEVICE The present application is a continuation-in-part of my co-pending application Ser. No. 107,328, filed Jan. 18, 1971 now abandoned.

BACKGROUND OF THE INVENTION While devices in accordance with the invention may be used in effecting other surface treatments, the removal of paint and mortar from bricks and paint and rust from metal surfaces, for example, the invention is discussed herein with particular reference to the removal of paint from wood, especially from buildings. Almost everyone is familiar with the problem of preparing a house or boat for repainting as loose paint must be removed and often it is desirable to so strip the wood as to completely clean its surface. Scrapers are effective only in freeing paint that is flaky and the use of heat and chemicals are objectionably slow where large areas are involved.

One approach to the problem is that represented by the US. Pat. to Walter, No. 3,216,04l, in which a rotary disc scraper was proposed provided with equally spaced saw blades detachably attached to the disc with their blades arcuate but with their outer ends spaced radially a substantially greater distance than their inner ends. This proposal was objectionable for various reasons including the facts that the disc was necessarily made rigid and that the disposition of the saw blade teeth was such that an abrading rather than a cutting action of the teeth would result in use.

THE PRESENT INVENTION The present invention provides rotary disc devices that are adapted to be attached to and rotated by such easily handled power operated tools as sanders or drills with each device including a disc and a coiled length of a band saw type of blade embedded therein with the cutting edges of the teeth exposed to establish an annular cutting zone of substantial radial extent and desirably, the disc is resiliently flexible.

In a preferred embodiment, each disc has a smooth surfaced periphery and a substantial portion of the outer turn of its coiled, embedded blade length is approximately concentric with said periphery and so closely adjacent thereto as to enable a layer-removing operation to be effected substantially against a shoulder abutting the area being treated.

It is preferred that each such coiled blade length has its outer and inner ends connected to the length to provide circular outer and inner turns and, additionally, providing a permanent assembly that facilitates the embedding of the blade length in the disc-forming material.

In embodiments, where the devices are particularly,

but not exclusively adapted for use in treating wood surfaces, the embedded, coiled blade length has its turns so closely spaced that all of its teeth have their cutting edges disposed substantially in the direction in which the device is rotated.

In embodiments where the devices are particularly but not exclusively adapted for use in treating such hard surfaces as brick and steel, the blade lengths have their teeth substantially in accordance with U. S. Pat. No. 3,537,491.

SHORT DESCRIPTION OF THE DRAWINGS In the accompanying drawings, there are shown embodiments of the invention illustrative of these and other of its objectives, novel features, and advantages in which:

FIG. I is a plan view ofa paint removing device in ac cordance with the invention;

FIG. 2 is a partly sectioned side view thereof;

FIG. 3 is a fragmentary and partly sectioned side view, on an increase in scale, illustrating the blade construction;

FIG. 4 is a fragmentary plan view of a paint removing device in accordance with another embodiment of the invention;

FIG. 5 is a fragmentary and partly sectioned side view thereof;

FIG. 6 is a plan view of a device in accordance with another embodiment of the invention;

FIG. 7 is a section, on an increase in scale, taken approximately along the indicated lines 77 of FIG. 6;

FIG. 8 is a plan view of yet another embodiment ofthe invention;

FIG. 9 is a section, on an increase in scale, taken approximately along the indicated lines 9-9 of FIG. 8; and

FIG. 10 is a fragmentary and partly sectioned edge view of the device of FIG. 8.

PREFERRED EMBODIMENTS OF THE INVENTION In the embodiment of the invention illustrated by FIGS. 1 3, the device consists of a flexible disc 10, rubber or plastic, and a coiled length of a saw blade 11 of the band saw type molded therein preferably with only its teeth exposed to provide an annular cutting zone with the teeth 12 disposed with their cutting edges leading in the direction the disc is to be rotated. It is preferred that, for removing paint from wood, there be 14 teeth per inch. The blade I 1 has a series of apertures 13 to ensure its becoming effectively anchored by the material in which it is embedded. Also molded in the disc is the apertured head 14 of a stem 15 extending through one face thereof to enable the device to be secured to a suitable portable, power operated tool, not shown, by which it may be rapidly rotated. Examples of such tools are sanders and drills. The coiled saw blade length 11 has its turns so closely spaced that they are substantially circular and occupy an annular portion of the disc of substantial radial extent spaced a substantial distance from the embedded head 14.

It is preferred that the discs of the devices be formed of polyurethane that, for example, in a six inch disc, seven-sixteenths of an inch in thickness, has that degree of resilient flexibility that will permit the disc to yield sufficiently, if held at an angle against the surface to be treated, to avoid digging into the wood.

In practice, the devices are produced as by providing a circular mold having an axial socket for the stem 15 and filled to a desired level with the polyurethane in a heated plastic state and with the head 14 supported in piace by its stern I5. The blade length is pressed therein in a coiled form with its teeth clear of the upper level of the plastic mass which is sufficiently fluid to flow through the apertures I3. The thus filled mold is then heat treated in an oven.

The embodiment of the invention shown in FIGS. 4 and 5 may be identical to that just described as to the construction of the disc 16 but the teeth 17 of the coiled length of the band saw blade 18 are shown as alternately being disposed in opposite lateral directions and the blade 18 is also shown as sinuous whereby each turn of the blade cuts a wide path both because of the set of the teeth and because of the waves in the blade. The anchoring apertures of the blade are shown as lengthwise slots 19.

In the embodiment of the invention illustrated by FIGS. 6 and 7, the device is generally similar to that shown in FIGS. 1 3 and the disc 20 is or may be similar to the disc 10. The coiled blade length 21, however, has its outer end 21A welded as at 22 to the proximate turn to provide a substantially circular outer turn and its inner end 218 also welded as at 23 to provide a substantially circular inner turn. It will be noted that the outer turn is located closely adjacent the smooth 'surfaced periphery of the disc 20 enabling surface treatments to be effected close to abutting shoulders. This arrangement of the blade also has the important advantage that the blade length is established as a coiled unit with all its turns substantially circular that may be placed in a mold without the necessity of otherwise confining its ends in the plastic. It is not essential that the inner turn be concentric for the resiliency of the blades tends to swing the turns slightly off-center but in all cases, the coiled length is confined to a relatively narrow annular zone spaced radially from the embedded perforated head 24 of the axial attaching stem 25 protruding from one face of the disc 20. The blade length 21 has holes 26 formed therein to ensure its secure anchorage in the disc 20. As in the case of the device shown in FIGS. 1 3, the teeth 27 are exposed on the other face of the disc 20.

The embodiment of the invention illustrated by FIGS. 8 10 is shown as generally similar to that just described except that the perforated head 28 of the attaching stem 29 is shown as square. The head 28 has a central square hole 28A for the squared end 29A of the stem. The head 28 and the coiled, slotted blade length 30 are embedded in the disc 31 with the stem 29 protruding from one side and the blade teeth 32 exposed on the other side of the disc. The teeth 32 are of the type disclosed in U.S. Letters Pat. No. 3,537,491 and are welded to the blade. The teeth 31 are of a cross sectional area. The cutting edges of the teeth are the peripheries of their circular, planar end faces and such teeth are particularly well suited for use, for example, in removing paint and mortar from bricks and paint and rust from metal surfaces.

In use, a device is attached to its driving too] by which is rapidly rotated and as the tool is manually moved over the surface to advance the device, the paint or other surface layer is quickly cut therefrom even if several coats or layers are present. The rate at which'the devices are rotated determines, of course, the rate of removal of the unwanted layer but is not otherwise important. A driving tool having a control enabling its speed to be varied has the advantage that the speed may be adjusted to that best adapted for a particular job by the operator.

I claim:

1. A device for use in removing paint or other surface layers from wood, metal, bricks, and the like and to be rotated by a power driver, said device comprising a resiliently flexible disc of a moldable material, a length of a blade of the band saw type embedded and anchored in the disc in such a manner that its teeth are exposed on a face thereof, and axial means exposed on the other face for attaching the disc to the driver, said embedded blade length being in the form of a coil having a plurality of closely spaced turns of such extent and being so disposed that it extends completely about said axial means while still permitting the disc to flex and includes inner and outer portions, the former spaced outwardly from the axial means, the latter located substantially at the periphery of the disc, and a plurality of intermediate portions spaced substantially uniformly from each other.

2. The device of claim 1 in which the axial means includes a head embedded in the disc and stiffening the central portion thereof and the blade means are located outwardly thereof.

3. The device of claim 1 in, which the disc has a smooth surfaced periphery, and the embedded blade length is in the form of a coil having a plurality of turns so closely spaced that substantially all of its teeth have their cutting edges disposed in the direction the device is to be rotated and having a substantial portion of its outer turn substantially concentric with the periphery of the disc and so closely adjacent thereto as to enable a layer-removing operation to be effected substantially against a shoulder abutting the area being treated.

4. The device of claim 3 in which the turns of the blade length are sufficiently close to establish a series of substantially circular portions.

5. The device of claim 3 in which the end of the blade length of the outermost turn is disposed in a trailing direction.

6. The device of claim 1 in which the blade means has a series of lengthwise apertures in its embedded portion through which it is anchored by the disc material.

7. The device of claim 3 in which the blade means is sinuous.

8. The device of claim 3 in which the teeth of the blade means are alternately offset in opposite directions.

9. The device of claim 1 in which each tooth is a vertical projection having a flat, circular work-engaging face.

10. The device of claim 3 in which the outermost turn of the embedded blade length overlaps and is connected to the other end of that turn.

1 l. The device of claim 10 in which the inner end of the innermost turn overlaps and is secured to the other end of that turn.

12. The device of claim 1 in which the blade length has fourteen teeth perinch. I

i i i l 

1. A device for use in removing paint or other surface layers from wood, metal, bricks, and the like and to be rotated by a power driver, said device comprising a resiliently flexible disc of a moldable material, a length of a blade of the band saw type embedded and anchored in the disc in such a manner that its teeth are exposed on a face thereof, and axial means exposed on the other face for attaching the disc to the driver, said embedded blade length being in the form of a coil having a plurality of closely spaced turns of such extent and being so disposed that it extends completely about said axial means while still permitting the disc to flex and includes inner and outer portions, the former spaced outwardly from the axial means, the latter located substantially at the periphery of the disc, and a plurality of intermediate portions spaced substantially uniformly from each other.
 2. The device of claim 1 in which the axial means includes a head embedded in the disc and stiffening the central portion thereof and the blade means are located outwardly thereof.
 3. The device of claim 1 in which the disc has a smooth surfaced periphery, and the embedded blade length is in the form of a coil having a plurality of turns so closely spaced that substantially all of its teeth have their cutting edges disposed in the direction the device is to be rotated and having a substantial portion of its outer turn substantially concentric with the periphery of the disc and so closely adjacent thereto as to enable a layer-removing operation to be effected substantially against a shoulder abutting the area being treated.
 4. The device of claim 3 in which the turns of the blade length are sufficiently close to establish a series of substantially circular portions.
 5. The device of claim 3 in which the end of the blade length of the outermost turn is disposed in a trailing direction.
 6. The device of claim 1 in which the blade means has a series of lengthwise apertures in its embedded portion through which it is anchored by the disc material.
 7. The device of claim 3 in which the blade means is sinuous.
 8. The device of claim 3 in which the teeth of the blade means are alternately offset in opposite directions.
 9. The device of claim 1 in which each tooth is a vertical projection having a flat, circular work-engaging face.
 10. The device of claim 3 in which the outermost turn of the embedded blade length overlaps and is connected to the other end of that turn.
 11. The device of claim 10 in which the inner end of the innermost turn overlaps and is secured to the other end of that turn.
 12. The device of claim 1 in which the blade length has fourteen teeth per inch. 